Ceramic rotor fabrication



7, 1963 N. D. HAZZARD ETAL 3,101,778

CERAMIC ROTOR FABRICATION Filed May 13, 1960 m mwroer win 4 awn/@9667 A ae/ 0. Azzaro I 3,101,778 CERAMIC ROTOR FABRICATION Noel D. Hazzard and John A. Cunningham, Wellsville,

N.Y., assignors, by mesne assignments, to Combustion Engineering, Inc., a stock corporation of Delaware Filed May 13, 1960, Ser. No. 28,980

2 Claims. (Cl. 165-10) 3,101,778 Patented Aug. 27, 1963 of a metallic spider 12 located at the .cold end of the rotor Where the deleterious effects of heat and corrosion are at a minimum. Therotor is in turn carried by a trunnion 14 that is rotated about its vertical axis by motive means not illustrated. A ceramic rotor post 16 is supported upon the hub of spider 12 concentrically with- The present invention relates to heat exchange apparatus, and more particularly it relates to a rotary regenerative heat exchange apparatus of a type that adapted is adapted for use in zones of very high temperature.

In rotary regenerative heat exchange apparatus a mass of heat exchange material carried in a rotor is first position-ed in a passage for a heating fluid to absorb heat from the fluid flowing therethro ugh, and upon turning the rotor about itsaxis, the heat exchange material is positioned in a spaced fluid passageway where it is free to transfer its absorbed heat to a fluid to .be heated. The rotor is surrounded by a housing having end or sector plates formed with openings therein to provide for the passage of the fluids, and to prevent their mingling, seal-- ing means are provided at the ends of the rotor to wipe against or pass in closely spaced relation with the imperforate pontion of the adjacent housing structure.

Such rotary regenerative heat exchange apparatus is generally considered to provide a most eflicient method of heat transfer, and the use of such apparatus is quite common at temperatures that lie within the working range of steel or the steel alloys that comprise the heat exchanger structure. However, for temperatures well above these limits as frequently prevail in various metallurgical and chemical processes the usual metallic rotary regenerative heat exchange apparatus is not suitable because of the temperature limitations of the material or because the contaminants in the fluids passing through the heat exchanger are not compatible with the metal in the higher temperature ranges.

Various attempts have been made to utilize ceramic materials as the heat absorbent element for apparatus of this type. However, the majority of these ceramic materials are subject to severe breakage when subjected to the thermal stresses brought about when a temperature gradient is placed on the element. Mechanical shock to the various ceramic elements creates an additional hazard which takes its tool in broken or damaged element, and as will be evident, continued thermal and mechanical shock tends to disintegrate the ceramic element and reduce it to an inoperative state.

Therefore, the chief object of this invention is to provide a novel arrangement for a ceramic rotor that substantially precludes damage from thermal and mechanical shock.

A further object of this invention is to provide spacing means between element blocks to provide for the free flow of fluid between superposed element blocks whose passageways do not coincide.

The manner in which these objects are carried out will be readily understood when viewed in conjunction with the accompanying drawings in which:

FIGURE 1 is a sectional elevation showing the rotary regenerative heat exchanger according to the invention.

FIGURE 2 is a perspective view of an element arrangement within the rotor, and

FIGURE 3 is a cross section of the invention.

vIn the drawing the numberal 8 represents the cylindri cal shell of a rotor that is formed of heat'resistant ceramic material preferably having a degree of natural resiliency that would preclude dam-age from thermal or mechanical shock. The rotor shell rests upon the annular periphery of a ceramic element spacer in cylindrical shell 8 to provide an annular space therebetween for a mass of ceramic heat transfer element 1 8 that comprises an annular series of sectorial blocks 3.

I The rotor is surrounded bya housing that comprises j a ceramic liner 22 within asteel casing 24, the annular space therebetween being packed 'with an insulating material 26 of resilient ceramic fiber. Other fibrous ceramic packing is provided around the rotor post 16, in the spaces 52 between blocks 39 and in the annular space between the assembled blocks 39 and the rotor shell 9. Since the element blocks 39 are completely surrounded by resilient packing material, they are relatively free to expand, contract or otherwise become distorted without adversely affecting the relationship of the variously cooperating elements. 7

The rotor housing is provided at opposite ends thereof with ceramic end or sector plates 32 and 34- having apertures 33 and 3-5 for the flow of heating fluid and the fluid to be heated to and through the block-s 39 of heat transfer element 18. A ceramic sealing plate 37 having an annular rim connected to a hub portion by radial spokes in alignment with the radial spaces between blocks 39 is pivotally carried by the upper end of rotor post 16. This sealing plate provides a floating sealing surface that adjusts itself to the plane of the adjacent sector plate to compensate for uneven axial deformation of the rotor. A resilient packing of fibrous ceramic material is inserted between the imperforate surface of the sealing plate 37 and the adjacent edge of the rotor to provide a sealing medium that expands or contracts as required to fill the varying space between adjacent elements and preclude the flow of fluid therethrough.

The mass of heat transfer element 18 comprises essentially an annular series of sector shaped ceramic blocks 39 having axial flow passageways for the flow of gases therethrough and imperforate sides that preclude the lateral flow of said gases between laterally adjacent blocks. The first annular series of sector shaped blocks is supported upon the metallic spider 12 while succeeding annular series of blocks are supported upon radial spacers 42 carried by the parallel shoulders of adjacent blocks 39. The spacers 42 being free at both ends may move axially and/or laterally in accordance with thermal distortion of the rotor elements. The spacers are formed of ceramic material extruded or otherwise formed with a cross-like transverse section that provides horizontal arms 44 to space axially adjacent element blocks wlhile vertical extensions 46 similarly space the laterally adjacent blocks.

Since the ceramic blocks 39 are inherently fragile and subject to deterioration from thermal and mechanical shock, the surfaces of spacers 42 are provided with strips of fibrous ceramic packing 48 having a natural resilience and resistance to shock that effectively isolates each block from other blocks adjacent thereto. The strips of ceramic packing may-be cemented to the plane surfaces of the spacers 42 to secure it in position during assembly of the rotor elements and to hold it in such position during operation of the rotor.

After assembly in the prescribed manner, the element blocks will be firmly but flexibly held on all sides by a resilient packing that precludes a surface to surface contact of adjacent blocks. Thus while the element blocks are restrained against bodily movement the resilient packing does permit limited expansion, contraction or other distortion that commonly prevails in such apparatus. Moreover the resilient packing provides a shock absorbing cushion for the rotor elements that substantially eliminates damage from mechanical shock during assembly.

While this invention has been described with reference to the embodiment illustrated in the drawing, it is evident that various changes may be made without departing from the spirit of the invention, and it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What We claim is:

1. A heat absorbent element mass for a rotary regenerative heat exchanger having a rotor carrying the element mass alternately between a heating fluid and a fluid to be heated; said heat absorbent element mass including a plurality of sector shaped blocks of porous ceramic element axially aligned about a central rotor post to provide a composite annular element; ceramic spacer elements carried by radially adjacent element blocks adapted to simultaneously provide a predetermined lateral spacing between adjacent blocks of element and a predetermined axial spacing between superposed annular banks of element; and resilient fibrous ceramic packing strips carried by the spacer elements adapted to provide a resilient support for the annular banks of element.

2. A rotary regenerative heat exchange apparatus including a rotor adapted to rotate about its central axis, said rotor including a metallic support frame having a rim portion supported by arms extending radially outward from a central hub, a cylindrical ceramic rotor shell mounted upon the rim of said support frame, a

ceramic rotor post concentric with the rotor shell carried by the hub of the support frame, sector shaped blocks of ceramic element carried by the metallic support frame in the annular space between the rotor shell and concentric rotor post, ceramic spacer elements carried by References Qited in the file of thispatent UNITED STATES PATENTS 2,428,461 Kinney et al 0a. 7, 1947 2,706,109 Odman Apr. 12, 1955 2,787,458 Reintjes Apr. 2, 1957 

1. A HEAT ABSORBENT ELEMENT MASS FOR A ROTARY REGENERATIVE HEAT EXCHANGER HAVING A ROTOR CARRYING THE ELEMENT MASS ALTERNATELY BETWEEN A HEATING FLUID AND A 